Japanese Unexamined Patent Application, First Publication No. 2014-175819 (Patent Literature 1) discloses an imaging system including electromagnetic wave detecting elements arranged in a two-dimensional array. In an imaging device using array type detecting elements, there are limitations on an imaging speed thereof from electrical restrictions when the elements are operated and a problem in that the imaging device is expensive and large in size.
Published Japanese Translation No. 2006-520893 of the PCT International Publication (Patent Literature 2) discloses a device using a single pixel detector. Furthermore, Japanese Patent No. 3444509 (Patent Literature 3) discloses an image reading device having single pixel detectors. An imaging device configured to perform single pixel detection needs to spatiotemporally structure illumination light to capture an image. For this reason, mechanical/electrical constraints involved in spatiotemporally changing illumination light occur and there are limitations on an imaging speed in the imaging device configured for single pixel detection.
For example, there are limitations on a speed of mechanically performing spatial-scanning with a laser in a confocal microscope and an image cannot be captured at high speed. Ghost imaging is a method in which numerous different structural lightings are radiated using a spatial light modulator or the like, detection is iterated, and an image is reconstructed. In such a method, since a speed of radiating lighting serves as a constraint, imaging is slow.
Japanese Unexamined Patent Application, First Publication No. 2013-15357 (Patent Literature 4) discloses a flow cytometer using serial time-encoded amplified microscopy (STEAM). In this publication, laser pulses with sufficiently wide wavelength widths are emitted from a laser irradiating unit at constant time intervals and the laser pulses are two-dimensionally dispersed by a two-dimensional spatial disperser. Different positions on a sample are irradiated with laser beams with wavelengths dispersed by the two-dimensional spatial disperser and the laser beams are reflected. The reflected laser beams with these wavelengths reversely pass through the two-dimensional spatial disperser so that the reflected laser beams return to one pulse. Such a pulse passes through a Fourier transform, a frequency component is converted into a time, and then the pulse is detected by a photodiode. In a continuous time encoding amplitude microscope method, since a frequency (a wavelength) corresponds to a position on a sample and a frequency component is converted into a time, the time has information of the position on the sample. In other words, a two-dimensional intensity distribution is converted into a time series. Information on surface structures of particles to be tested can be obtained from a temporal change in intensity signals of pulses acquired in this way.
In a serial time-encoded amplified microscopy (STEAM), repetition on frequency of a pulsed laser becomes constraints. Furthermore, an imaging device using STEAM is very expensive and large in size, an applicable light wavelength range is limited to long wavelengths, and thus it is difficult to achieve high sensitivity in a visible light range. For this reason, there is a problem in that STEAM cannot be applied to a visible fluorescence wavelength region necessary for application to the fields of life sciences/medicine.